Polymerization Of Pyrrole Monomer Research Articles

Photo-Initiated in situ synthesis of polypyrrole Fe-Coated porous silicon microspheres for High-performance Lithium-ion battery anodes

A simple and environmentally friendly photoinitiated fabrication approach based on the photoelectric effect of semiconductor silicon is designed to synthesize yolk-shell like polypyrrole-iron coated porous silicon microspheres (PSi@PPy-Fe) as anode materials for LIBs. The polymerization of pyrrole monomers only occurs on the interface of silicon matrix where the vacancies are available, which effectively avoids the production of free PPy-Fe particles. XPS and first-principles calculations reveal that both the hydrogen-bond interaction and the covalent linkage are formed between Si and PPy-Fe layer, which is of great significance for maintaining good contact and strengthening the structure stability. It is demonstrated that the PPy-Fe coating may accelerate charge transfer and ion diffusion as well as prevent the Si-based materials peeling off from Cu collector. More importantly, the PPy-Fe coating could alleviate the violent structural expansion of Si anode, thus ameliorating the mechanical strength of the electrode. Consequently, the as-prepared yolk-shell like polypyrrole-iron coated porous silicon microspheres present outstanding cycling ability (1853.7 mAh/g after 200 cycles at 1 A/g) and superior rate capability (1558.4 mAh/g at 4 A/g). This work indicates that the photochemical modification strategy for Si may have a bright prospect in a wide range of fields.

Semi‐Crystalline Polypyrrole with Enhanced Electrochemical Properties Enabled by Air–Water Interface Confined Polymerization

AbstractPolypyrrole (PPy) represents an intriguing class of materials for high‐performance pseudocapacitor electrode due to their fast and reversible Faradaic redox reaction. However, these pseudocapacitors suffer from several disadvantages such as low capacitance and charge/discharge cycling instability, which can be attributed to the poor charge‐transfer capability and stability of PPy. Previously, it is found that charge hopping is more efficient in the crystalline domain of PPy, and thus higher charge‐transfer capability can be achieved from PPy with higher crystallinity. However, the polymerization of pyrrole monomers usually forms randomly entangled chains, which results in PPy with a high fraction of amorphous domains. Therefore, synthesis of PPy with higher crystallinity remains challenging. Here, air–water interface‐confined polymerization (ICP) strategy is introduced to synthesize PPy with enhanced crystallinity. Three kinds of crystalline PPy with different dopants (chlorion ion, 4‐[[4‐(dimethylamino)phenyl]diazenyl]benzenesulfonate anion, and β‐naphthalene sulfonate anion) are synthesized via ICP. The PPy synthesized from ICP is demonstrated to have an improved electrochemical performance. This work will shed light on the synthesis methods and mechanisms to form PPy with improved crystallinity and electrochemical performances.

Salt Template-Derived Fe-N Co-Doped Ultrathin Carbon for Boosted Performance of Supercapacitors

Heteroatoms-doped ultrathin carbon materials hold great promise for electrochemical energy application. Herein, we develop a salt-templating method to prepare three-dimensional Fe-N co-doped carbon (FeNPC) with ultrathin (~ 5-nm-thick) structural feature. The synthetic procedure involves the following steps: First, fabrication of nanoNaCl templates with uniform particle sizes (~500 nm) via one-pot solution synthesis. Second, fabrication of the precursor by encapsulating of NaCl nanoparticles via the in-situ polymerization of pyrrole monomers under vapor atmosphere. Last, FeNPC formation by subsequent pyrolysis and pickling. The optimized sample displays excellent performance as supercapacitors exhibiting 393.5 F g-1 at 1A g-1 in 6 M KOH. Furthermore, the symmetric supercapacitors assembled with the optimized sample show an energy density of 10.45 Wh kg-1 at a power density of 300 W kg-1 and outstanding cycling stability retaining 93% capacitance at 5A g-1 after 10000 cycles.

Composite Nanofibers by Growing Polypyrrole on the Surface of Polyaniline Nanofibers Formed under Free Melting Condition and Shell-Thickness-Dependent Capacitive Properties

An efficient approach was presented to prepare polyaniline/polypyrrole (PANi/PPy) composite nanofibers by growing PPy layers on the surface of PANi nanofibrous seeds as electrode materials for supercapacitors in neutral electrolyte. Core layer of PANi nanofiber was firstly synthesized by the chemical oxidative polymerization of aniline monomers under free melting condition of reaction solutions in fully aqueous system without the assistance of any templates or organic solvents. Then the shell layer of PPy was fabricated by in-situ chemical oxidative polymerization of pyrrole monomers with the above-mentioned PANi nanofiber as a seed, and the PPy shell layer thicknesses were tuned by changing the molar ratio of aniline to pyrrole. The resulting PANi/PPy composites were investigated by field-emission scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared and Raman spectrometry. Furthermore, electrochemical behaviors in Na2SO4 electrolyte were tested by cyclic voltammetry, galvanostatic charge-discharge techniques and electrochemical impedance spectroscopy. It turned out that low molar ratio of aniline to pyrrole is helpful to increase the PPy shell layer thicknesses, yield and conductivity of PANi/PPy composite nanofibers. A great improvement on the capacitive properties could be achieved by choosing appropriate PPy shell layer thickness. The results showed that benefiting from strong synergy effect and π-π interaction between PANi core and PPy shell layer as well as low electrochemical impedance, PANi/PPy composite nanofibers prepared with the molar ratio of 1:1 (PPy shell layer thickness of about 12.5 nm) displayed the highest specific capacitance of 1550.2 F g−1 at scan rate of 5 mV s−1 and 758.8 F g−1 at the current density of 1 A g−1 with the best cycling stability of 70.3 % after 500 cycles in 0.5 M Na2SO4 electrolyte, which exhibited a great potential in the development of high-performance electrode materials operated in environmentally friendly electrolyte.

Adsorptive removal of V(V) ions using clinoptilolite modified with polypyrrole and iron oxide nanoparticles in column studies

AbstractClinoptilolite modified with polypyrrole and iron oxide nanoparticles (Cln-PPy-Fe3O4) nanocomposite as a potential adsorbent for V (V) ions was prepared via polymerization of pyrrole monomer using FeCl3 oxidant in aqueous medium in which clinoptilolite-Fe3O4 nanoparticles were suspended. The structure and morphology of the prepared adsorbent was analysed with the Fourier transform infrared (FTIR) spectrometer, field-emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and high-resolution transmission electron microscope (HR-TEM). Column fixed bed studies were performed to test the ability of the adsorbent to remove V (V) ions from aqueous solution. Low values of adsorbent exhaustion rate (AER) and large bed volumes were observed at lower metal ion concentration, higher bed mass and lower flow rate for V(V) removal indicating good performance. The volume of treated water processed at breakthrough point were found to be 0.09; 0.63 and 1.26 L for bed mass of 1, 2.5; and 5 g, respectively. The Yoon–Nelson and Thomas models appropriately described the breakthrough curves.

One-step polypyrrole coating of self-assembled silver nanoprisms for enhanced stability and Raman scattering

Self-assemblies of silver nanoprisms (AgPRs) having enhanced structural stability and optical properties have been facilely coated with polypyrrole (PPy) via the in situ polymerization of pyrrole monomers that also act as an assembling agent. The assemblies of AgPRs, whose edge lengths and thicknesses are typically 78 and 4 nm, respectively, have been surrounded by a PPy coating of 6 nm. AgPRs are assembled in a side-to-side orientation, and the degree of assembly has been controlled by varying the concentration of trisodium citrate dihydrate, which attaches selectively to the {111} facets of AgPRs. The morphology deformation time of PPy-coated AgPRs in 0.6 mM H2O2(aq) is seven times longer than that of PPy-free AgPRs, suggesting that PPy coating prevents the sharp tips of AgPRs from being truncated by oxidizing agents. The SERS effect of highly self-assembled and PPy-coated AgPRs becomes as high as 6.3 due to numerous hot spots generated between nanoprisms. Overall, our fabricated AgPRs assemblies with PPy coating have not only improved structural stability but also enhanced optical properties, extending the practical use of noble-metal nanoprisms for various optical applications.

Novel antifouling nano-enhanced thin-film composite membrane containing cross-linkable acrylate-alumoxane nanoparticles for water softening

A novel thin-film composite (TFC) nanofiltration membrane was prepared using polymerization of pyrrole monomers on the PES ultrafiltration membrane. To improve the characteristics of hydrophobic polypyrrole (PPy) thin-film layer, cross-linkable acrylate-functionalized alumoxane nanoparticles with different concentrations were embedded into the thin-film during polymerization process, and thin-film nanocomposite (TFNC) membranes were prepared. The characteristics and performance of TFC and TFNC membranes were assessed through the morphological analyses (SEM, AFM), measurement of hydrophilicity and solid–liquid interfacial free energy, water permeability and Mg2+ removal tests. Addition of proper amount of nanoparticles into the polymerization mixture led to the preparation of membranes with more hydrophilic, thinner and smoother active layer as well as higher water permeability compared to TFC control membrane. TFNC membrane prepared with 0.025g of nanoparticles was the most efficient membrane since it exhibited the highest rejection of MgCl2 and MgSO4 salts. Antifouling capability of membranes, in terms of flux recovery and fouling parameters, demonstrated the high tolerance of TFNC against fouling.

Vanadium (V) adsorption isotherms and kinetics using polypyrrole coated magnetized natural zeolite

Magnetized natural zeolite-polypyrrole (MZ-PPY) composite as a potential adsorbent for vanadium was prepared via polymerization of pyrrole monomer using FeCl3 oxidant in aqueous medium in which magnetized natural zeolite particles were suspended. The MZ-PPY composite was characterized by attenuated total reflectance Fourier transform infrared spectroscope (ATR-FTIR), field emission scanning electron microscope (FE-SEM) and high resolution transmission electron microscope (HR-TEM). Batch adsorption studies were performed to test the ability of the adsorbent to remove V(V) ions from aqueous solution. From sorption equilibrium modelling, the equilibrium data is well described by Langmuir, Sips and Redlich–Peterson isotherms while the adsorption kinetics is described by the pseudo-second order model. The Langmuir adsorption capacity is 65.0 mg/g at 298K. Thermodynamic parameters confirm the spontaneous and endothermic nature of the vanadium adsorption process. Meanwhile V(V) removal process is found not to be affected by co-existing ions. Furthermore, the material can be used in two adsorption cycles without compromising its capacity.

Synthesis of 1-D ZnO nanorods and polypyrrole/1-D ZnO nanocomposites for photocatalysis and gas sensor applications

1-D ZnO nanorods and PPy/1-D ZnO nanocomposites were prepared by the surfactant-assisted precipitation and in situ polymerization method, respectively. The synthesized nanorods and nanocomposites were characterized by UV–Vis spectrophotometer, Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM), which gave the evidence of 1-D ZnO nanorods, polymerization of pyrrole monomer and strong interaction between PPy and 1-D ZnO nanorods, respectively. Photocatalytic activity of 1-D ZnO nanorods was conducted by 33 level full-factorial design to evaluate the effect of three independent process variables viz., dye concentration (crystal violet), catalyst concentration (1-D ZnO nanorods) and the reaction time on the preferred response: photodegradation efficiency (%). The PPy/1-D ZnO nanocomposites were used for the sensing of NH3, LPG, CO2 and H2S gases, respectively, at room temperature. It was observed that PPy/1-D ZnO nanocomposites with different 1-D ZnO nanorod weight ratios (15 and 25%) had better selectivity and sensitivity towards NH3 at room temperature.

Synthesis of hierarchical reduced graphene oxide/SnO2/polypyrrole ternary composites with high electrochemical performance

The hierarchical reduced graphene oxide/SnO2/polypyrrole ternary composites are prepared in a one-pot method via in situ redox reaction between graphene oxide and Sn2+ ions, followed by the polymerization of pyrrole monomers in the presence of methyl orange. The ternary composites are composed of one-dimensional polyprrole nanofibers and SnO2 nanoparticles distributed in the network of graphene nanosheets. Supercapacitors based on the hierarchical composite show larger specific capacitance compared with the ternary composite prepared without methyl orange and reduced graphene oxide/SnO2 binary composite. They also exhibit superior electrochemical rate capability and cyclic stability. The capacitance retained about 95% after 800 galvanostatic cycles at 1A/g. The high electrochemical performance results from the hierarchical nanostructure, the efficient combination of components and the synergistic interaction among the three components. The hierarchical ternary composites are promising electrode material for high-performance supercapacitors.

<i>In Situ</i> Polymerization Synthesis of Ternary Sulfur/Polypyrrole/Graphene Nanosheet Cathode for Lithium/Sulfur Batteries

A novel sulfur/polypyrrole/graphene nanosheet composite (S/PPy/GNS) was synthesized and investigated as a promising cathode material. This ternary composite was prepared via in situ polymerization of pyrrole monomer with nanosulfur and GNS aqueous suspension followed by heat-treatment. Scanning electronic microscopy observation revealed the formation of a highly porous structure consisting sulfur and polypyrrole coating on the GNS surface. In this composite, GNS works as nanocurrent collector and enhances the conductivity of the composite, and polypyrrole with its high adhesion ability to GNS could act as a binder to connect sulfur and GNS. The resulting S/PPy/GNS composite cathode exhibits high and stable specific discharge capacities of 991 mAh g-1 after 50 cycles at 0.1 C and good rate capability.

Synthesis of polypyrrole/indium tin oxide nanocomposites via miniemulsion polymerization

Polypyrrole/indium tin oxide nanocomposites were synthesized via in situ miniemulsion polymerization of pyrrole monomer in the presence of indium tin oxide nanoparticles. Different nanocomposites were synthesized by different loadings of nano indium tin oxide. The morphology and nanoparticles distribution of the nanocomposites were characterized by electron microscopy. The results of XRD and TEM analysis showed that indium tin oxide nanoparticles were well placed in the polymeric structure of latex. FTIR analysis was used for the characterization of synthesized polypyrrole and its nanocomposites. TGA analysis was performed to investigate the thermal behavior of pristine polypyrrole and its nanocomposites. Conductivities of nanocomposites were measured by 4-point probe method and compared to the neat polymer.

NiCr x Fe2−x O4 ferrite nanoparticles and their composites with polypyrrole: synthesis, characterization and magnetic properties

Nanocrystalline nickel chromium ferrite (NiCr x Fe2−x O4, x = 0.1, 0.2) have been prepared by the chemical co-precipitation method. Half of the samples have been sintered at 620∘C and the other at 1175∘C. Then polypyrrole (PPy)–NiCr x Fe2−x O4 composites have been synthesized by polymerization of pyrrole monomer in the presence of NiCr x Fe2−x O4 nanoparticles. The structure, morphology and magnetic properties of the samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer. Also, the initial magnetic permeability measurements as functions of temperature and frequency have been performed. The XRD and FT-IR studies have confirmed the well crystalline phase of ferrite nanoparticles, and the presence of amorphous PPy in the composite samples. The SEM and TEM images have obviously clarified the coating of ferrite nanoparticles by PPy in the composite samples. The hysteresis loop of the samples has proved that the samples are soft magnetic material because of their low coercivity.

Assembly of Polypyrrole-Graphene Oxide Hydrogel Nanocomposites and Their Swelling Properties

An effective one-step strategy for the static assembly of hydrogels from polypyrrole (PPy) and graphene oxide (GO) is demonstrated. The static polymerization of pyrrole monomer was carried out in the presence of GO nanosheets, leading to the formation of PPy-GO hydrogels. During the static polymerization process, gelation takes place simultaneously by supramolecular interactions. The well-dispersed GO nanosheets in the polymer networks resulted in a significant improvement in water absorbencies. With only a very low loading of GO in the PPy-GO hydrogels, they exhibited significantly larger water uptake compared to a PPy hydrogel. Even in saline solutions, PPy-GO hydrogels also showed obvious water absorbency. Moreover, the PPy-GO hydrogels exhibited a better water retention ability compared with the control under the same conditions. This method is believed to provide possibilities to combine the extraordinary performances of GO with the multifunctional properties of conducting polymers, thus holding great potential for technical applications in the future.

Sulphate Doped Polypyrrole Encapsulated Tin Composite for the Lithium Ion Battery Anode

Tin is considered as a promising candidate for the lithium ion anode which is synthesized by co-precipitation technique using stabilizing agents such as C-TAB. The conducting Sn-sulphate doped polypyrrole is synthesized by polymerization of pyrrole monomers in the nano tin particles dispersed in 0.1% PVP + water medium using ammonium per sulphates as a polymerizing as well as doping agent. The XRD, SEM and TEM analysis confirms the formation of polypyrrole coated on tin nano particles to form a composite. Pulverization effect of tin metal electrode is the highly significant challenge to solve while charge-discharge process, thus while lithium insertion and desertion process the polymer based conductive material like polypyrrole (conductive polymer) coated on tin nano particle holds the active material to avoid isolation from the conductive matrix, which act as a current collector. The coating thickness is being optimized by the various weight ratios of polymer to tin nano particles from 5 to 20%. The thickness of the coating is analyzed by SEM and TEM; the electrochemical behavior is investigated by EIS and charge-discharge studies. 80:20 ratio of tin-polypyrrole composite gives almost 100% capacity retention at the rate 400 mA g-1 and delivers initial specific discharge capacity of 878 mAh g-1 Figure 1

Structural investigation of anionic functional poly(vinyl alcohol) doped polypyrrole nanospheres

This article reports on a facile route for the preparation of polypyrrole nanospheres with improved water solubility, ordering and conductivity in the presence of a polyelectrolyte, such as phosphorylated polyvinyl alcohol. The phosphorylated polyvinyl alcohol (PPVA) was used as both the stabilizer and the dopant in the chemical oxidative polymerization of pyrrole. The resulting PPVA doped polypyrrole (PPy) nanocomposites (PPy-PPVA) were characterized with FTIR, TGA, SEM and AFM techniques. The electrical conductivity of polymer was measured by four-point probe method. Our observation and results suggest a plausible formation mechanism of PPy nanospheres, PPVA micelle might have functioned as ‘template’ during the polymerization of pyrrole monomers, meanwhile, the PPy chains doped with phosphate group. It was found that the size decreased and their dispersion stability in water increased with the increasing feeding ratio of PPVA. The conductivity of PPy with different morphologies was also measured and compared. When the PPVA: pyrrole feeding ratio ranged from 20 to 50 wt%, the PPy-PPVA nanoparticles showed spherical shape with excellent uniformity, good electrical conductivity (up to 33.1 S·cm−1), and weakly temperature dependent conductivity. It’s worth mentioning that the PPy-PPVA nanocomposite prepared in high PPVA feeding ratio has been well-dispersed for more than 24 months, which indicates its significant dispersion stability.

Microporous gel electrolyte for quasi-solid-state dye-sensitized solar cell

The extension of electrocatalytic reaction of I−/I3− from counter electrode/gel electrolyte interface to gel electrolyte can significantly enhance the redox kinetics and therefore conversion efficiency of dye-sensitized solar cells. Microporous gel electrolyte from polypyrrole integrated poly(hydroxyethyl methacrylate/cetytrimethylammonium bromide) [PPy-integrated poly (HEMA/CTAB)] is successfully synthesized by in-situ polymerization of pyrrole monomers in three-dimensional framework of porous poly(HEMA/CTAB) matrix. An ionic conductivity of 12.72 mS cm−1 and activation energy of 8.65 kJ mol−1 are obtained from PPy-integrated poly(HEMA/CTAB) gel electrolyte. Tafel polarization and electrochemical impedance spectroscopy are employed to characterize the electrocatalytic behaviors of the gel electrolytes. The resultant quasi-solid-state dye-sensitized solar cell shows a light-to-electrical conversion efficiency of 6.68%. POLYM. ENG. SCI., 54:2531–2535, 2014. © 2013 Society of Plastics Engineers

Conductive Polypyrrole/Polyurethane Composite Fibers for Chloroform Gas Detection

Flexible conductive fibers were fabricated by in-situ chemical polymerization of pyrrole monomers on the surface of polyurethane (PU) fibers. Compact polypyrrole (PPy) surface layer were observed, and moreover, high structural stability of the composite fibers can be obtained due to interpenetrating interface formation and strong interaction between PPy layers and PU matrix. More importantly, the composite fibers exhibited high sensitivity with relative fast response and recovery time, and good reproducibility for chloroform vapor detection.

Synthesize, Characterization, and Corrosion Inhibition of Polypyrrole Thin Films on Copper

Polypyrrole (PPy) coatings were synthesized on copper by electrochemical polymerization of pyrrole monomer in aqueous acidic and basic solutions by cyclic voltammetry. The coatings were characterized with CV, UV-visible absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) techniques. The corrosion protection aspects of PPy coatings have been investigated using the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements show that the PPy coating has ability to protect the copper against corrosion. It was concluded that a complete corrosion protective PPy film could not be obtained through direct electro-oxidation procedure. This may be due to copper dissolution in the monomer oxidation potential range.

Polypyrrole top-contact electrodes patterned by inkjet printing assisted vapor deposition polymerization in flexible organic thin-film transistors

Highly conductive polymer, polypyrrole (PPy) was successfully patterned as source and drain (S/D) electrodes for flexible pentacene thin film transistors in top-contact structure by combining inkjet printing and vapor deposition polymerization. Facile inkjet printing of initiator and subsequent exposure of pyrrole monomers resulted in selective absorption and polymerization of pyrrole monomers on the patterned initiator region. Pentacene transistors based on printed PPy electrodes exhibited higher electrical characteristics than that of the devices with thermally evaporated Au electrodes. Improved performance of the devices based on PPy electrodes could be attributed to the reduction of contact resistance at the interface between polymer and organic semiconductor. For the replacement of metal electrodes, vapor deposition polymerization assisted inkjet printing technique can provide a versatile method to utilize highly conductive polymer as a functional electrode of flexible organic electronic devices.